1 files changed, 23 insertions, 5 deletions

diff --git a/fs/char_dev.c b/fs/char_dev.c
index 0009346d827f..33b95af89da4 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -128,13 +128,31 @@ __register_chrdev_region(unsigned int major, unsigned int baseminor,
 
         for (cp = &chrdevs[i]; *cp; cp = &(*cp)->next)
                 if ((*cp)->major > major ||
-                    ((*cp)->major == major && (*cp)->baseminor >= baseminor))
+                    ((*cp)->major == major &&
+                     (((*cp)->baseminor >= baseminor) ||
+                      ((*cp)->baseminor + (*cp)->minorct > baseminor))))
                         break;
-        if (*cp && (*cp)->major == major &&
-            (*cp)->baseminor < baseminor + minorct) {
-                ret = -EBUSY;
-                goto out;
+
+        /* Check for overlapping minor ranges.  */
+        if (*cp && (*cp)->major == major) {
+                int old_min = (*cp)->baseminor;
+                int old_max = (*cp)->baseminor + (*cp)->minorct - 1;
+                int new_min = baseminor;
+                int new_max = baseminor + minorct - 1;
+
+                /* New driver overlaps from the left.  */
+                if (new_max >= old_min && new_max <= old_max) {
+                        ret = -EBUSY;
+                        goto out;
+                }
+
+                /* New driver overlaps from the right.  */
+                if (new_min <= old_max && new_min >= old_min) {
+                        ret = -EBUSY;
+                        goto out;
+                }
         }
+
         cd->next = *cp;
         *cp = cd;
         mutex_unlock(&chrdevs_lock);